The state of the art includes continuously rotating shears of the type as in this invention. The blades of the shears are always in rotation and they are brought to the shearing position at the desired moment by bringing nearer the respective axes of rotation with a parallel displacement.
It is quite clear that in this type of shears there are problems of synchronisation both between the blades and also between the blades and the shearing moment; there are also problems concerning the transmission of power.
If these problems are not properly solved they entail anomalous wear, vibrations, interferences, breakages, incorrect or incomplete shearing, excessive maintenance and a loss of the shearing wire.
An experiment has been carried out in which motion is supplied directly to both the blade-bearing drums.
This experiment also provides that the drums are supported at the respective ends by cams.
The cams of one drum cooperate with the cams of the other drum so as to define the shearing moment on each occasion.
Synchronisation is achieved by means of toothings located at the end of the drums and outside the cams.
When the cams are made to rotate so as to take the blades into the shearing position, the toothings cooperate with each other correctly.
When the cams are made to rotate so as to take the blades into the non-shearing position, while they continue to rotate around their axis, the toothings are distanced and remain connected only through the tips of the teeth and not along the primitive circumference.
The resulting connection is therefore extremely precarious.
A command organ, acting on a pair of cams connected to a drum, drives both the pairs of cams so as to provide, on each occasion, the shearing position.
It is quite evident that this solution known to the state of the art entails discontinuous efforts, uncertain synchronisation, two drive inlets, vibrations, etc.
The present applicant has designed, tested and embodied this invention to overcome the shortcomings of the state of the art and to obtain further advantages.